Caffeine does not increase the risk of atrial fibrillation: a systematic review and meta-analysis of observational studies.

Laboratory of Clinical Pharmacology and Therapeutics, Faculty of Medicine, University of Lisbon, , Lisboa, Portugal.
Heart (British Cardiac Society) (Impact Factor: 6.02). 10/2013; 99(19):1383-9. DOI: 10.1136/heartjnl-2013-303950
Source: PubMed

ABSTRACT Atrial fibrillation (AF) is the most prevalent sustained arrhythmia, and risk factors are well established. Caffeine exposure has been associated with increased risk of AF, but heterogeneous data exist in the literature.
To evaluate the association between chronic exposure to caffeine and AF.
Systematic review and meta-analysis of observational studies.
PubMed, CENTRAL, ISI Web of Knowledge and LILACS to December 2012. Reviews and references of retrieved articles were comprehensively searched.
Two reviewers independently searched for studies and retrieved their characteristics and data estimates.
Random-effects meta-analysis was performed, and pooled estimates were expressed as OR and 95% CI. Heterogeneity was assessed with the I(2) test. Subgroup analyses were conducted according to caffeine dose and source (coffee).
Seven observational studies evaluating 115 993 individuals were included: six cohorts and one case-control study. Caffeine exposure was not associated with an increased risk of AF (OR 0.92, 95% CI 0.82 to 1.04, I(2)=72%). Pooled results from high-quality studies showed a 13% odds reduction in AF risk with lower heterogeneity (OR 0.87; 95% CI 0.80 to 0.94; I(2)=39%). Low-dose caffeine exposure showed OR 0.85 (95% CI 0.78 to 92, I(2)=0%) without significant differences in other dosage strata. Caffeine exposure based solely on coffee consumption also did not influence AF risk.
Caffeine exposure is not associated with increased AF risk. Low-dose caffeine may have a protective effect.

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    Heart (British Cardiac Society) 10/2013; 99(19):1377-8. · 6.02 Impact Factor
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    ABSTRACT: The association between habitual caffeine intake with incident atrial fibrillation (AF) was unknown. We conducted a meta-analysis to investigate the association between chronic exposure of caffeine and the risk of AF and to evaluate the potential dose-response relation. We searched PubMed, EMBASE, and the Cochrane Library up to November 2013 and references of relevant retrieved articles. Prospective cohort studies were included with relative risk (RR) or hazard ratio and 95% confidence intervals (CIs) for AF according to coffee/caffeine intake. Six prospective cohort studies with 228,465 participants were included. In the primary meta-analysis, caffeine exposure was weakly associated with a reduced risk of AF (RR, 0.90; 95% CI, 0.81-1.01; P = 0.07; I(2) = 73%). In subgroup analyses, pooled results from studies with adjustment of potential confounders showed an 11% reduction for low doses (RR, 0.89; 95% CI, 0.80-0.99, P = 0.032; I(2) = 30.9%, P = 0.227) and 16% for high doses (RR, 0.84; 95% CI, 0.75-0.94, P = 0.002; I(2) = 24.1%, P = 0.267) of caffeine consumption in AF risk. An inverse relation was found between habitual caffeine intake and AF risk (P for overall trend = 0.015; P for nonlinearity = 0.27) in dose-response meta-analysis and the incidence of AF decreased by 6% (RR, 0.94; 95% CI, 0.90-0.99) for every 300 mg/d increment in habitual caffeine intake. It is unlikely that caffeine consumption causes or contributes to AF. Habitual caffeine consumption might reduce AF risk.
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